Calibrator Purity Audit for the Hubble-Constant Distance Ladder

A data-analysis service that screens Milky-Way standard candles used to anchor the Hubble constant — Gaia-parallax Cepheids and other nearby calibrators — for unresolved close companions, and delivers per-star contamination reports plus a corrected, companion-clean calibrator set. It targets one specific systematic: stellar blending that biases calibrator photometry and astrometry.